Major depressive disorder

Major Depressive Disorder (MDD), also known simply as depression, is a mental disorder characterized by at least two weeks of pervasive sadness or a lack of interest in activities, accompanied by additional psychological or physical symptoms. These symptoms can include changes in sleep patterns, appetite, energy level, concentration, daily behavior, or self-esteem. Depression can also be associated with thoughts of suicide.

Symptoms and Signs

The primary symptoms of Major Depressive Disorder include persistent sadness, a feeling of emptiness, and anhedonia – a lack of pleasure in normally enjoyable activities. Other symptoms may involve feelings of worthlessness or guilt, irritability, fatigue, changes in appetite and weight, difficulty sleeping or oversleeping, psychomotor agitation or retardation, difficulty concentrating, and recurrent thoughts of death or suicide.

Causes

The etiology of Major Depressive Disorder is multifactorial, with contributions from genetic, biological, environmental, and psychological factors. Genetics play a significant role, with heritability estimates ranging from 30% to 40%. Neurobiological theories suggest alterations in neurotransmitter levels, including serotonin, norepinephrine, and dopamine, are involved. Environmental factors, such as trauma or stress, and psychological factors, like personality traits or coping mechanisms, also significantly contribute to the development of MDD.

Diagnosis

Diagnosis of Major Depressive Disorder is based on the patient's self-reported experiences, behavior reported by relatives or friends, and a mental status examination. There are no laboratory tests for MDD, but tests may be conducted to rule out other conditions that may cause similar symptoms. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria are commonly used for diagnosis, which require the presence of five or more symptoms over a two-week period, with at least one of the symptoms being either persistent sadness or anhedonia.

Treatment

Treatment for Major Depressive Disorder may involve a combination of psychotherapy, antidepressant medication, and, in some severe cases, electroconvulsive therapy (ECT) or other brain stimulation therapies. Cognitive-behavioral therapy (CBT) and interpersonal therapy (IPT) are among the most effective forms of psychotherapy for MDD. Selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly prescribed antidepressants. Treatment plans should be tailored to the individual, taking into account the severity of symptoms, previous treatment history, and the patient's preferences.

Epidemiology

Major Depressive Disorder is one of the most common mental disorders worldwide. It affects millions of adults and adolescents, with a higher prevalence among women. The disorder can develop at any age, but the median age of onset is in the late 20s.

Prognosis

The prognosis for individuals with Major Depressive Disorder varies. Some individuals experience a single depressive episode and fully recover, while others may have recurrent episodes or chronic depression. Early treatment and ongoing management can improve the long-term outlook for many people with MDD.

See Also

• Bipolar Disorder
• Anxiety Disorders
• Psychotherapy
• Antidepressant Medication